In an imaging forming apparatus, i.e., a so-called electronic copier utilizing digital technology, a document glass on which an original is placed is exposed to light, image signals corresponding to the amount of light reflected from the document glass are obtained from a CCD (charge-coupled device) type line sensor, a photoconductive drum is irradiated by laser beams corresponding to the image signals obtained form the line sensor, thereby forming an electrostatic latent image on a peripheral surface of the photoconductive drum, and the electrostatic latent image is clarified by adhering a developing agent (toner) which is previously charged (negatively).
A sheet of paper is sent to the photoconductive drum in good timing to the rotation of the photoconductive drum, and the clarified image (developing agent image) on the photoconductive drum is transferred to the sheet of paper. In this manner, the sheet on which the developing agent image is transferred is sent to a fusing apparatus.
The fusing apparatus comprises a heating roller and a pressure roller. While the sheet of paper is sandwiched between both the rollers for transferring the sheet, the developing agent image on the sheet is fused by heat of the heating roller. The fused sheet is ejected to a tray.
In such an electronic copier, control program data are stored. When the program data are rewritten into new program data, a personal computer, e.g., is connected to a body of the electronic copier, and the new program data stored in the personal computer are downloaded into a memory within the body. By this download, the old program data are overwritten with the new program data.
However, when the program data in the memory is overwritten with the new program data, an abnormal condition may occur in the rewritten program data in some cases. With the program data in which the abnormal condition occurs, the electronic copier can not operate appropriately.
The present invention has been accomplished in view of the above circumstances, and it is an object of the invention to provide a reliable and excellent imaging forming apparatus which can promptly return newly rewritten program data into old program data before rewritten when the new program data cause abnormal condition, and which can avoid unnecessary halting of the apparatus.
An imaging forming apparatus of the present invention comprises:
a first memory in which control program data are stored,
a second data storing memory,
an inputting section for inputting data,
first control means for storing the program data in the first memory into the second memory and then, writing the program data input by the inputting section into the first memory, and
second control means for writing the program data in the second memory if necessary after the program data are written by the first control means.